Function Reference

DllStructCreate

Parameters

[optional] If supplied the struct will not allocate memory but use the pointer supplied.

Return Value

Success:

a variable for use with DllStruct calls.

Failure:

sets the @error flag to non-zero.

@error:

1 = Variable passed to DllStructCreate was not a string.
2 = There is an unknown Data Type in the string passed.
3 = Failed to allocate the memory needed for the struct, or Pointer = 0.
4 = Error allocating memory for the passed string.

Type

Details

BYTE

8bit(1byte) unsigned char

BOOLEAN

8bit(1byte) unsigned char

CHAR

8bit(1byte) ASCII char

WCHAR

16bit(2byte) UNICODE wide char

SHORT

16bit(2bytes) signed integer

USHORT

16bit(2bytes) unsigned integer

WORD

16bit(2bytes) unsigned integer

INT

32bit(4bytes) signed integer

LONG

32bit(4bytes) signed integer

BOOL

32bit(4bytes) signed integer

UINT

32bit(4bytes) unsigned integer

ULONG

32bit(4bytes) unsigned integer

DWORD

32bit(4bytes) unsigned integer

INT64

64bit(8bytes) signed integer

UINT64

64bit(8bytes) unsigned integer

PTR

32 or 64bit pointer (depending on if the x86 or x64 version of AutoIt is used)

HWND

32 or 64bit pointer (depending on if the x86 or x64 version of AutoIt is used)

HANDLE

32 or 64bit pointer (depending on if the x86 or x64 version of AutoIt is used)

FLOAT

32bit(4bytes) floating point

DOUBLE

64bit(8bytes) floating point

INT_PTR, LONG_PTR, LRESULT, LPARAM

32 or 64bit signed integer (depending on if the x86 or x64 version of AutoIt is used)

UINT_PTR, ULONG_PTR, DWORD_PTR, WPARAM

32 or 64bit unsigned integer (depending on if the x86 or x64 version of AutoIt is used)

STRUCT

The following datatypes will be align according to C declaration rules. See below.

ENDSTRUCT

End of the collection datatypes. Padding can occurs see below.

ALIGN

n bytes boundary where datatype must be aligned.

Remarks

Each data type must be separated by a semi-colon ';'.

Create arrays by adding '[size]' after the data type: DllStructCreate("int;char[128]")

An elementname can be added similar to a C-style declaration: DllStructCreate("int n;char buffer[128]").
This dataname can be used in place of the element in other DllStruct... functions. The dataname must be alphanumeric or an underscore.

If a collection of datatypes is defined as in a "struct{}" in C declaration, the "STRUCT; ...; ENDSTRUCT;" must be used.
This needs to be done to respect alignment inside the entire structure creation. No need if all datatypes are in the defined structure as an implicit structure alignment is done.

DllStructCreate("int;STRUCT;ptr;int;ENDSTRUCT;int") ; structure is 32 bytes under a Windows 64-bit and 16 under Windows 32-bitDllStructCreate("int;ptr;int;int") ; structure is 24 bytes under a Windows 64-bit and 16 under Windows 32-bit

To use a different alignment prefix the structure with the align keyword. The default value for n is 8. Valid values are 1, 2, 4, 8, and 16. The alignment of a member will be on a boundary that is either a multiple of n or a multiple of the size of the member, whichever is smaller. This is equivalent to the #pragma pack option with the Microsoft Visual C++ compiler.

DllStructCreate("short;int") ; structure is 8 bytes, the "int" is at offset 4DllStructCreate("align 2;short;int") ; structure is 6 bytes, the "int" is at offset 2

DllStructCreate("byte;double") ; structure is 16 bytes, the "double" is at offset 8DllStructCreate("align 4;byte;double") ; structure is 12 bytes, the "double" is at offset 4

If a change of alignment is needed "align" can be use before the first element which need to be changed.
"align" or "align 8" leads to default alignment.

To release allocated memory just set the returned variable to 0.

The following aggregate alignment rules apply:
The alignment of an array is the same as the alignment of one of the elements of the array.

The alignment of the beginning of a structure is the maximum alignment of any individual member.
Each member within the structure is be placed at its proper alignment as defined in the previous table, which require implicit internal padding, depending on the previous member.

Structure size is an integral multiple of its alignment, which requires padding after the last member.

Related

Example

#include<MsgBoxConstants.au3>Example()Func Example()#cs Comments: Create the following structure (C language): struct { int var1; unsigned char var2; unsigned int var3; char var4[128]; }; Schema: ------------------------------------ \ int \ byte \ uint \ char \ \ var1 \ var2 \ var3 \ var4 \ ------------------------------------ #ce; Assign a Local constant variable the definition of a structure (read carefully the DllStructCreate remarks).LocalConst$tagSTRUCT1="struct;int var1;byte var2;uint var3;char var4[128];endstruct"; Note: The tag variable is declared as Constant because its value will never change for any script execution.; Assign a Local variable the structure.Local$tSTRUCT1=DllStructCreate($tagSTRUCT1); If an error occurred display the error code and return False.If@errorThenMsgBox($MB_SYSTEMMODAL,"","Error in DllStructCreate, Code: "&@error)ReturnFalseEndIf; Set the data of the element var1 (int) in the $tSTRUCT1.DllStructSetData($tSTRUCT1,"var1",-1); Or 1 instead of "var1".; Set the data of the element var2 (byte) in the $tSTRUCT1.DllStructSetData($tSTRUCT1,2,255); Or "var2" instead of 2.; Set the data of the element var3 (uint) in the $tSTRUCT1.DllStructSetData($tSTRUCT1,"var3",-1); The -1 (signed int) will be typecasted to unsigned int.; Or 3 instead of "var3".; Set the data of the element var4 (char) in the $tSTRUCT1.DllStructSetData($tSTRUCT1,"var4","Hello"); Or 4 instead of "var4".; Note: This element can contain up to 128 characters.; Change the data of the element var4 (char) in the $tSTRUCT1, at the index 1 of the char array (1 based index).DllStructSetData($tSTRUCT1,"var4",Asc("h"),1); Display the results.MsgBox($MB_SYSTEMMODAL,"","Struct Size: "&DllStructGetSize($tSTRUCT1)&@CRLF&_"Struct pointer: "&DllStructGetPtr($tSTRUCT1)&@CRLF&_"Data:"&@CRLF&_DllStructGetData($tSTRUCT1,1)&@CRLF&_; Or "var1" instead of 1.DllStructGetData($tSTRUCT1,"var2")&@CRLF&_; Or 2 instead of "var2".DllStructGetData($tSTRUCT1,3)&@CRLF&_; Or "var3" instead of 3.DllStructGetData($tSTRUCT1,4)); Or "var4" instead of 4.; Release the resources used by the structure.$tSTRUCT1=0EndFunc;==>Example